Method of manufacturing alkylaluminum compounds

ABSTRACT

A method of manufacturing alkylaluminum compounds from ternary or quaternary alloys, comprising as principal elements aluminum, silicon and titanium, and aluminum, silicon, titanium and iron, respectively, wherein said alloys are reacted with hydrogen and an aluminum alkyl. An olefin and/or a catalyst may also be added in the reaction.

United States Patent Kobetz et al. Aug. 29, 1972 [54] METHOD OF MANUFACTURING R ferences Cited ALKYLALUMINUM COMPOUNDS UNITED STATES PATENTS [72] Inventors: Paul Kobetz, Baton Rouge, La; 3 381 024 4/1968 To yoshima et al.....260/448 A m Becker 3,402,190 9/1968 Toyoshima et al.....260/448 A 3,050,540 8/1962 Gould ..260/448 A [73] Assignee: Ethyl Corporation, New York, 3,050,541 8/1962 Gould ..260/448 A N.Y. 3,393,217 7/1968 lchiki et al ..260/448 A [221 Fil 16,19 0 Primary Examiner-Tobias E. Levow 21 A 1 N 9 9 4 Assistant Examiner-H. M. S. Sneed 1 PP 0 5 Attorney-Donald J. Johnson, John F. Sieberth, Paul Related U.S. Application Data H. Leonard and Arthur G. Connolly [60] Continuation-impart of Ser. No. 42,555, June 1, 1970, abandoned, which is a division of Ser. [57] ABS CT No. 860,097, Sept. 22, 1969, Pat. No. A method of manufacturing alkylaluminum com- 3,535,108, which is a continuation-in-part of pounds from ternary or quaternary alloys, comprising Ser. No. 653,622, July 17, 1967, abandoned. as principal elements aluminum, silicon and titanium, and aluminum, silicon, titanium and iron, respectively, [52] U.S. Cl. ..260/448 A wherein said all ys ar reacted with hydrogen and an [51] Int. Cl. ..C07f 5/06 aluminum alkyl. An olefin and/or a catalyst may also [58] Field of Search 4.260/448 A be added in the reaction.

41 Claims, N0 Drawings METHOD OF MANUFACTURING ALKYLALUMINUM COMPOUNDS CROSS-REFERENCES TO RELATED APPLICATIONS This is a continuation-in-part of application Ser. No. 42,555, now abandoned filed June 1, 1970, which in turn is a division of earlier application Ser. No. 860,097, filed Sept. 22, 1969, now U. S. Pat. No. 3,535,108, which in turn is a continuation-in-part of still earlier application Ser. No. 653,622, filed July 17, 1967, now abandoned.

BACKGROUND OF THE INVENTION It is well known .that organo aluminum and/or aluminum alkyl compounds may be produced .by reacting aluminum with an organo aluminum compound and hydrogen or with an olefin and hydrogen in the presence of an organoaluminum compound. See, for example, U. S. Pat. Nos. 2,787,626; 2,900,402; 2,930,808; 3,000,919; 3,016,396; 3,032,574; 3,207,770; 3,207,772; 3,207,773; 3,207,774; 3,393,217; and 3,505,375.

U. S. Pat. No. 3,393,217 discloses the production of organo aluminum compounds using an aluminum-silicon binary alloy containing more than 13 percent by weight of silicon. The patent further discloses that impurity amounts of iron, copper, titanium and magnesium may also be present in the binary alloy. These impurity amounts are quite small however, usually about 0.1 percent by weight or less of the binary aluminum-silicon alloy.

U. S. Pat. No. 3,393,217 further discloses that binary aluminum-silicon alloys of 13-60 percent by weight silicon produce far greater depletions during hydroalumination than binary aluminum-silicon alloys containing less than 13 percent silicon by weight. Extremely poor depletions or aluminum extractions are obtained (less than percent) when the silicon content of the binary alloy is as low. as about 8 percent silicon by weight.

U. S. Pat. No. 3,402,190, which relates to a method for manufacturing alkylaluminum compounds utilizing certain activators or catalysts, discloses that with the use of such catalysts, namely alkoxides of lithium, sodium or potassium, alkylaluminum compounds can be made from multi-component alloys such as aluminumsilicon-iron or aluminum-silicon-iron-titanium, the alloys having the composition of 13-40 percent by weight of silicon, l-15 percent by weight of iron, 0-10 percent by weight of titanium and the remaining amount being aluminum. Small amounts of other metals such as magnesium and calcium may also be included in the alloy.

Although some degree of success has been achieved using these prior art processes, it has been unexpectedly discovered that consistently superior depletions may be obtained by reactions involving ternary and quaternary alloys comprising namely aluminum, silicon and titanium, and aluminum, silicon, titanium and iron, respectively, wherein the titanium is present in an amount sufficient to speed up the hydroalumination reaction, but not in an amount sufiicient to have a deleterious effect on the amount of the aluminum which can be reacted out of the alloy.

SUMMARY OF THE INVENTION It is a primary object of this invention to provide a process whereby an organo aluminum compound or aluminum alkyl can be prepared from a ternary or quaternary alloy, namely an alloy comprising as its principal elements aluminum, silicon and titanium, or aluminum, silicon, titanium and iron. The titanium must also be present in an amount of at least 0.2 percent by weight of the ternary or quaternary aluminum alloy. The remaining elements may be present in varying amounts, however, aluminum must be present in at least about 33 percent by weight and the other components proportionately.

The ternary or quaternary alloy of the present invention consists essentially of, by weight percent, aluminum 33-94, silicon 5-58, titanium 0.2-4 and iron 0-5. Accordingly this invention provides a method for producing alkylaluminum compounds, which comprises reacting an aluminum-silicon ternary or a quaternary alloy comprising 33 to 94 percent by weight of aluminum, 5 to 58 percent by weight of silicon, 0 to 5 percent by weight of iron, and 0.2 to 4 percent by weight of titanium with an alkylaluminum compound, hydrogen and a catalytic substance. An olefin may also be added in the reaction.

Titanium must be present in more than impurity amounts and in an amount sufficient to speed up or enhance the hydroalumination reaction. The titanium must also be in sufficiently small amounts that it does not have a deleterious effect on the reaction. In the quaternary alloy, i.e., when iron is present, it is generally preferable that the amount of titanium exceed the amount of the iron; however, when the amount of iron is small, excellent results are obtained even when the amount of the iron exceeds the amount of the titanium.

In general, it is preferred that both titanium and iron be in as small amounts as will effectively enhance vthe hydroalumination reaction. The less iron in the quaternary alloy, the more titanium that can be tolerated and conversely the more iron in the alloy, the less titanium that can be tolerated.

The titanium unexpectedly overcomes the deleterious effect of silicon in a hydroalumination reaction using binary aluminum-silicon alloys as taught in U. S. Pat. No. 3,393,217.

The present invention consistently provides depletions of percent or more in the hydroalumination reaction. It should be noted that increases of depletions of even 1 percent are extremely important in a commercial process.

When an aluminum alkyl is used as a principal reactant, stoichiometric amounts are used. When an olefin is used in the reaction, only catalytic amounts of the aluminum alkyl are necessary.

BRIEF DESCRIPTION OF PREFERRED EMBODIMENT The ternary aluminum-silicon-titanium alloy or the quaternary aluminum-silicon-iron-titanium alloy is preferably activated for use in the reaction, as in the case of aluminum, and the activation may be carried out according to any of the known processes proposed in the case of aluminum metal which are effected by I triphenylaluminum,

crushing or cutting the alloy in a hydrocarbon solvent containing a small amount of an organo aluminum compound, by jetting the alloy in a molten state into a protective liquid under an inert atmosphere or by using an activator such as a trialkylaluminum, dialkylaluminum hydride or halide or the like, or sodium ethoxide, other alkoxy compounds or other suitable activators.

In one embodiment of the invention, shavings or small particles of a ternary or quaternary aluminum alloy, comprising as principal elements aluminum, silicon and titanium or aluminum, silicon, titanium and iron, respectively, are reacted with 1.5 times the theoretical amount of triisobutylaluminum with hydrogen at 1500 psig at 120C for about 7 to 15 hours.

In another embodiment of the invention wherein a more reactive aluminum alkyl is used such as triethylalurninum, good results are obtained at a hydrogen pressure of 1000 psig at 140C for about 1 to 3 hours. The ternary or quaternary alloy may contain impurity amounts of copper, magnesium, calcium, zirconium, vanadium and other elements.

The amount of aluminum to be contained in the alloy is preferably more than 50 percent by weight, but can be as low as 33 percent by weight.

The amount of silicon to be contained in the alloy can be any amount from about 5 to about 58 percent by weight of the alloy.

The amount of titanium in the alloy is at least 0.2 percent by weight and preferably not more than about 4 percent by weight. A weight percent of titanium from about 0.6 to about 3 is especially preferred.

The amount of iron in the alloy is preferably as little as possible but may be from to 5 percent by weight, and alloys containing less than 4 percent iron are preferred. A weight percent of iron of about 1 to about 4 is especially preferred.

The alloy may be finely divided or in any desired shape such as chipped-like fragments obtained by use of a shaper, lathe or drilling machine, or chunks or small particles obtained by simple crushing or cutting.

The alkylaluminum compound employed as one of the materials used in the present invention is represented by the general formula, RR'AIR", wherein R and R are respectively selected from alkyl radicals having two to 20 carbon atoms and R" is selected from the group consisting of alkyl radicals, hydrogen or halogen. Preferred alkylaluminum compounds are triethylalurninum, diethyl-aluminum hydride, di-npropylaluminum hydride, trim-propylaluminum, triisobutylaluminum, diisobutylaluminum hydride and mixtures thereof.

Some examples of other suitable alkylaluminum compounds are ethyl-di-propylaluminum, diethylaluminum chloride, diethyl-aluminum bromide, diisobutylaluminum chloride, diisobutylalurninum bromide, dioctylaluminum chloride, dioctylaluminum bromide, dipentadecylaluminum chloride, dipentadecylaluminum bromide, didocosylaluminum chloride, diphenylaluminum hydride, diphenyl-aluminum chloride, dipara-tertiary-butylphenylaluminum hydride, di-paratertiary-butylphenylaluminum chloride, phenyloctylauminum hydride, phenyloctylaluminum chloride,

tripara-tertiary-butylphenylaluminum, diphenyloctylaluminum, dioctyl-aluminum hydride, dipentadecylaluminum hydride, didocosylaluminum hydride, ditetracontylaluminum hydride, trioctylaluminum, tripentadecylaluminum and tridocosylaluminum.

The olefin which may be employed in the present invention-is preferably an alpha olefin having two to twenty carbon atoms of which typical examples are ethylene, propylene, normal and isobutylene, 2-methyll-pentene, and 2-ethyl-l-hexene. Olefins having internal double bonds are less reactive and are thus not as desirable.

Catalysts employed in the present invention may be selected from the group of alkali metals and alkaline earth metals and their hydrides, halides, alkyls and alkoxides or complexes of these compounds with alkylaluminum compounds.

A preferred catalyst for use in the present invention has the formula MYn.Al(C H )RX, wherein M is an alkali metal or an alkaline earth metal; Y is hydrogen (H), chlorine (Cl), fluorine (F), hydroxyl group (OH), cyanide group (CN), alkyl group (R) or alkoxy group (OR n is an integer in accordance with the valences of M and Y; R is hydrogen or a hydrocarbyl group selected from alkyl, alkenyl, alkynyl, aralkyl, aryl and alkaryl having up to twenty carbon atoms; and X is halogen or the same as R. Catalysts of hydrocarbyl groups of C to C are preferred.

A most preferred catalyst is a sodium alkylaluminum hydride, e.g., sodium triethylalurninum hydride, sodium tetraethylaluminum and sodium diethylaluminum dihydride. Particularly good results have been obtained using a catalyst of the formula Nal-l'xTEA-yDEAl-l, wherein x y 5, but may equal at least 1 and preferably equals 3 to 5. (TEA is triethylalurninum and DEAH is diethylaluminum hydride.)

Preferred alkali metals are sodium, potassium and lithium, with sodium being the most preferred. Preferable alkaline earth metals are magnesium and calcium, with calcium being the more preferred.

Some examples of MY compounds are sodium hydride, sodium hydroxide, sodium cyanide, potassium chloride, sodium ethoxide, sodium butoxide and potassium butoxide.

Some examples of alkyl groups (R) are ethyl, propyl, isobutyl, n-butyl, sec-butyl, pentyl, hexyl, heptyl, octyl, octadecyl, and eicosyl. Alkyl groups having from two to four carbon atoms are most preferred.

Some examples of alkoxy groups (OR") are ethoxy, n-propoxy, isopropoxy, n-butoxy, phenoxy and ptolyloxy.

Some examples of hydrocarbyl groups (R) and (X) are ethyl, propyl, isobutyl, n-butyl, sec-, pentyl, hexyl, heptyl, octyl, decyl, eicosyl, lauryl, benzyl, cyclohexyl, vinyl, ethynyl, phenyl, tolyl, xylyl, mesityl, naphthyl, fluorenyl, and indenyl.

Some examples of halides are chloride, bromide and fluoride.

The complex metal compound catalyst may be prepared or formed in situ or may be added to the hydroalumination reactants.

Another suitable catalyst or activating agent which may be employed in the present invention is represented by the general formula, R MY, wherein R is selected from the group of alkoxy, aroxy, aralkoxy, alkaroxy, alkyl, aryl, aralkyl, and alkaryl radicals, Y is selected from the group of alkoxy, aroxy, aralkoxy and alkaroxy radicals, M represents a metal element having valency of n 1, and n is a whole number selected from 0, 1 and 2. Typical examples of the catalyst include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, phenoxy, and p-tolyloxy compounds of lithium, sodium and potassium; dimethoxy, diethoxy, diisopropoxy, din-butoxy, methoxy-ethoxy, ethyl-ethoxy, diphenoxy, methyl-phenoxy, and ethyl-tolyloxy compounds of magnesium and zinc; trimethoxy, triisopropoxy, tri-nbutoxy, dimethoxy-ethoxy, methyl-dimethoxy, ethyl diethoxy, dimethyl-methoxy, diethyl-ethoxy, n-butyldi-n-butoxy, diisobutyl-n-butoxy, triphenoxy, tribenzyloxy, and methyl-diphenoxy compounds of boron and aluminum.

The reaction temperatures to be adopted in the production of alkylaluminum compounds from the ternary or quaternary aluminum alloy are in the range of from 70C to 250C, preferably from 100C to 180C. Suitable reaction pressures are in the range of from to 300 kglcm Under pressures of less than 10 kilograms per square centimeter, the reaction velocity is low, whereas under pressures of more than 300 kglcm the reaction apparatus should necessarily be made complex and is not practical.

In a preferred embodiment of the invention, small particles of a quaternary aluminum alloy about -100 mesh in size, comprising, by weight percent, 78 aluminum, 20 silicon, 1 iron and 1 titanium are reacted with triethylaluminum, ethylene and hydrogen at 1000 psig at 140C for about 1 hour.

In accordance with the method of the present invention, a metal residue containing a large amount of silicon, which has been used in the production of the alkylaluminum, is separated from the reaction mixture, formed into an alloy of a suitable proportion and then may be used again. In such case, the metal residue may be recycled in the form of silicon containing impurity amounts of iron and titanium by converting the free aluminum present in the alloy into an alkylaluminum compound, or may be recycled in the form of an alloy or mixture comprising aluminum, silicon and titanium, with and without iron, by converting only a part of alu' minum present in the alloy.

In order to facilitate understanding of the invention, the following examples are set forth to illustrate the invention, but are not to be construed as limiting the scope thereof.

EXAMPLE A Two series of alloys were prepared for study. Both series had varying amounts of silicon from 0 to approximately 50 percent.

Each alloy was prepared by weighing the calculated amount of commercially pure metals into a graphite crucible which was heated in an induction furnace to 1400-1450C for series (A) or l800-1950C for series (B). The molten mixture was stirred with a graphite rod and allowed to cool. The ingot was treated with a rasp to remove the graphite crucible and then taken down on a lathe to remove the ends and outer skin.

The alloy ingots were comminuted by means of a lathe, taking a cut of about 0.004 inch (4 mils). The tumings were found to be thicker than 4 mils, smooth on one side and jagged on the other. They were of similar dimensions, about one-sixteenth inch wide, roughly one-eighth to one-fourth inch long, and averaging 6 to 8 mils thick. Two exceptions were Samples 1(A) and 2(A), which gave larger, thicker chips averaging about 9-13 mils thick. In general, the higher silicon alloys gave shorter, more brittle chips. The 16 mesh fines were removed from all of the alloy tumings. Samples for testing in the hydroalumination reaction were split out by quartering from the bulk sample.

X-ray fluorescence analyses (XRF) of these alloys are shown in Tables I and II.

Into a 300 milliliter stirred Magnedrive autoclave manufactured by Auto Engineers, quantity of alloy calculated to contain about 3.6 grams of aluminum and 6.8 milliliters of a sodium ethylalurninum hydride solution to give 0.6 weight percent sodium based on triisobutylaluminum (TIBA), and milliliters (79 grams) of TIBA, were charged. The TIBA contained 8 percent diisobutyl-aluminum hydride (DIBAH). The TIBA/Al mole ratio was close to 3.0, representing 50 percent excess of TIBA over theory (for run No. 8 TIBA/A1 3.4).

The catalyst solution was prepared from the reaction of sodium with a mixture containing approximately 70 percent diethyl-aluminum hydride (DEAH), 30 percent triethylaluminum (TEA), and filtering off the aluminum metal formed. It analyzed 8.1 percent sodium. The composition of the catalyst is not stoichiometric and is best represented by the general formula NaH-x- Et Al-yEt AlH (x y 5, but may equal at least 1 and preferably equals 3 to 5 After charging with alloy, TIBA and catalyst the autoclave was closed, pressurized to 1000 psig with hydrogen and heated to C with stirring. Then more hydrogen gas was introduced into the autoclave until the pressure became 1500 psig. This pressure and temperature were maintained for 5 hours. The pressure was then increased to 1750 psig and the reaction carried out for an additional 10 hours. The pressure at shut-down time (unattended) ranged from 1500-1750 psig. The total reaction time was 15 hours.

The reaction mixtures were worked up under nitrogen with special care to recover all of the solid residue. A benzene stream from a wash bottle was used to remove solids adhering to the stirrer, and to transfer the solids to a medium frit Buchner funnel. The residues were washed well with benzene and petroleum ether, vacuum dried on the filter and weighed.

All of the feeds, and those residues which were inhomogeneous [especially l(A) and 2(A)]were freezemilled in a Spex Freezer Mill at 196C before analysis. This was done to assure that the samples would be homogeneous.

The amounts of aluminum reacted in the two series are shown in Tables III and IV.

TABLE I Elemental Analysis of Series (A) Alloy Composition TABLE II Elemental Analysis of Series (B) Alloy Composition Sample Target Actual (XRF) No. A1. S1 Ti Fe Al. Si Ti Fe C 1(8) 89.5 0.0 6.0 4.5 87.1 0.2 1.4 5.0 1.45 2(3) 832 7.2 5.5 4.1 79.2 7.6 1.8 3.8 2.08 3(B) 73.1 18.3 4.9 3.7 72.2 16.8 2.6 2.5 2.45 4(B) 64.7 27.7 4.3 3.2 64.0 21.9 3.1 1.4 4.45 5(B) 56.1 37.4 3.7 2.8 58.5 31.8 3.2 1.2 170 TABLE III Results for Series (A) Run Alloy Alloy Residue Aluminum No. No. Charge, g Wt, g Reacted* 1 1(A) 3.70 0.23 97 2 2(A) 4.00 0.38 102 3 3(A) 4.60 1.03 101 4 4(A) 5.24 1.46 102 5 5(A) 6.10 2.07 98 Based on weight loss, aluminum reacted (Alloy Charge Residue Wt)/(Alloy Charge X A1)X 100 A series of alloys was prepared for determining the effect of titanium on the depletion of aluminum-silicontitanium alloys. The alloys were prepared similarly to those of series A in Example A.

Nominal compositions of these alloys are shown in Table V.

Hydroalumination was carried out following the procedure of Example A. In all runs, 100 ml of TIBA, 3.6 g of aluminum and 0.5 g of sodium as Nal lxTEA-yDEAH were reacted for 7.5 and hours at 1500 psig hydrogen.

The amounts of aluminum reactedare set forth in Table VI.

The beneficial effects of titanium in aluminum-silicon ternary and quaternary alloys containing titanium and titanium and iron, respectively, are readily apparent TABLE v Elemental Analysis of Alloy Series of Example B Alloy Sample No.

Al Si Ti Fe 1 so 0 0 2 79 19 1 1 3 79 8 0 0 4 91 s 1 0 TABLE VI Effect of Titanium in Ternary and Quaternary Alloys Run Alloy Thickness, Reaction Aluminum No. Sample Mils Time, Hrs. Reacted 1 1 z 10 7.5 79 2 1 z 10 15 99 3 2 6-8 7.5 101 4 2 6-8 15 103 5 3 z 10 15 36 6 4 10 7.5 99 7 4 10 15 EXAMPLE C For comparative purposes, binary aluminum-silicon alloys of van'ous amounts were tested. The alloys were commercially prepared alloy powder blown from the melt in an inert atmosphere by a reputable manufacturer. The composition of the alloys and a sieve analysis of each sample are set forth in Table VII.

Hydroalumination reactions were carried out following the procedure of Example A using TIBA at C, 1500 psig hydrogen for 15 hours using a catalyst. The results of these tests are set forth in Table VHI.

TABLE VH Composition of Blown Powders by XRF Analyses Alloy Weight Percent by XRF No. Mesh size Al. Si Ti Fe TABLE VIII TIBA Depletions of Blown Powders Alloy MOI/Ratio Run Sample Mesh TIBA/Al Aluminum No. No. Size Approx. Catalyst Reacted" l 1 20/40 3 A 8.2 2 1 100/200 3 A 28.5 3 2 20/40 3.2 A 25.3 4 2 100/200 3.2 A 44.3

A NaH-X TEA-Y DEAI-l, liquid sodium complex. Catalyst concentration 0.6 wt Na on TIBA. "Based on weight loss. Assumes nominal Al concentration in alloy EXAMPLE D Another series of alloy powders of various elemental compositions similarly blown from the melt as in Example C were obtained from the same reputable commercial source. The elemental compositions of these samples are set forth in Table IX.

Hydroalumination reactions were carried out following the procedure of Example A using TIBA at 120C, 1500 psig hydrogen for hours. The results of these tests are set forth in Table X.

TABLE IX Composition of Blown Powders by XRF Analyses Alloy Weight Percent by XRF No. Mesh size Al Si Ti Fe TABLE X Depletion of Blown Powders Run Aluminum No. Alloy No. Catalyst Reacted 5 3 A 99.2 6 4 A 75.7 7 5 A 44.2

A NaHx TEA-y DEAH "Based on weight loss EXAMPLE E A Hydroalumination reaction was carried out using triethylaluminum (TEA) as the aluminum alkyl and the procedure described in Example A. Four grams of quaternary alloy No. 4 (see Table IX in Example D) were reacted with 87 milliliters TEA and 6 milliliters of the sodium ethylalurninum hydride catalyst at 140C under 2000 psig hydrogen pressure for 3 hours. The reaction mixture was worked up as described in Example A and yielded 1.75 grams of solid residue. This weight of residue corresponds to a 90.4 percent depletion of the aluminum values present in the original aluminum-silicon quaternary alloy.

EXAMPLE F A sample of aluminum-silicon quaternary alloy was prepared by melting the calculated amounts of commercially pure metals to achieve the target composition. by percent by weight of 56 Al 31 Si 2 Ti 11 Fe. The molten alloy was cooled, crushed and ground and sieved through a -l00 mesh screen. X-ray fluorescence (XRF) analysis showed the actual iron content to be 7.9 percent and the titanium to be 2.2 percent. Four grams of this alloy were .reacted with 87 milliliters TEA in the presence of sodium ethyl-aluminum hydride catalyst at 140under 2000 psig hydrogen pressure for 3 hours. The reaction mixture was worked up as described in Example E. On the basis of the weight of solid residue recovered, the depletion of the aluminum values in the original quaternary alloy was only 73 percent. This points out the deleterious effect of excessively high iron content on the depletability of aluminum-silicon alloys in the hydroalumination reaction.

A similar experiment was conducted with an alloy prepared similarly and having a target composition by weight percent of 5 Ti and 4 Fe. Actual composition by XRF was 4.6% Fe and 5.0% Ti. Reaction of this alloy with TEA, catalyst and hydrogen at 140C, 2000 psig hydrogen for 3 hours, yielded a quantity of solid residue corresponding to an percent depletion of the aluminum values in the original alloy sample. This result illustrates the combined unfavorable effect of high iron and high titanium on the depletability of quaternary aluminum-silicon alloys in the hydroaluminatjon reaction.

The excellent depletions of ternary and quaternary alloys are clearly demonstrated in Examples D and E.

Aluminum tied up as interrnetallics is unreactive and preferably the amount of these interrnetallics should be kept as low as possible by keeping the amount of iron and titanium as low as possible.

In the initial step of a thermal decomposition process for producing aluminum as described in our copending application Ser. No. 42,555, which is hereby incorporated herein, crude aluminum or an aluminum-silicon alloy is converted into a dialkyl-aluminum hydride-containing liquid phase and a residual solids phase. The crude aluminum or aluminum-silicon alloy must contain some metallic aluminum which is not held in the tightly bound form of an interrnetallic compound. Aluminum-silicon alloys are especially preferred as materials to be refined in this process. Aluminum-silicon alloys can readily be produced at low cost by various electrotherrnic reduction processes and thereby serve as an economical source for purified aluminum metal. Moreover the residual solids formed in the present process will comprise metallic silicon (usually but not necessarily associated with other common impurities such as iron, titanium and the like). Such residual solids, which can be readily recovered, are of considerable utility in the chemical and allied arts, for example, in steel making processes. In addition, the by-product silicon from the process tends to be very active and thus may be reacted directly with alkyl halides to produce alkyl halosilanes. Thus, the use of the preferred aluminum-silicon alloys, especially those which contain small amounts of titanium and/or iron, is of advantage in that they are an economical source for low cost aluminum and yield in the present process useful silicon-containing by-products which are likewise of industrial and economical importance.

The crude aluminum or aluminum-silicon alloy is preferably employed in subdivided or particulate form, although effective use may be made of turning, chips, flakes, ribbons, and the like.

In practicing the first step of the decomposition process, there are two general methods for converting the crude metallic aluminum or aluminum-silicon alloy into the dialkyl aluminum hydride-containing liquid phase. One such method involves reacting the aluminum content with appropriate quantities of an alphaolefin (e.g., ethylene, propylene, isobutylene, etc.) and hydrogen in the presence of an alkylaluminum catalyst (e.g., triethylaluminum). In this way, it is possible to convert this aluminum content into a product which in most cases comprises the corresponding dialkylaluminum hydride and trialkylaluminum compounds. As is well known, it is desirable to suitably activate the aluminum so as to reduce the induction and reaction times. These reactions are generally carried out at somewhat elevated temperatures and pressures.

The other, and more preferred, method for converting the aluminum-silicon alloy into the dialkylaluminum hydride-containing liquid phase involves reacting the crude aluminum with appropriate quantities of trialkylaluminum and hydrogen. This reaction proceeds very smoothly and under proper conditions, quite rapidly, whereby dialkylaluminum hydride can be formed in good yield. Moreover, the use of this type of process makes it possible to recycle or reutilize the trialkylaluminum co-product which is formed in the aluminum-producing step.

Therefore, a preferred embodiment of the decomposition process involves converting the aluminumsilicon alloy into an alkylaluminum hydride-containing liquid phase and residual solids by reacting the aluminum with trialkylaluminum and hydrogen under appropriate reaction conditions. Such conditions preferably include use of aluminum-silicon alloy, activation of the aluminum by common techniques, and utilization of suitable elevated temperature and pressure conditions.

The foregoing first step may be modified, if desired, so as to produce other suitable alkylaluminum hydridecontaining liquid phases. Thus, although it is preferable that the liquid phase contain a significant proportion of dialkylaluminum hydride, this liquid phase may contain in addition to or in lieu thereof other alkylaluminum hydrides. Moreover, the reaction among the aluminumsilicon alloy, trialkylaluminum and hydrogen may be effected in admixture with a tertiary amine, such as those described above. In this case, the alkylaluminum hydride product(s) (and the trialkylaluminum almost always copresent) will tend to exist in the form of alkylaluminum-tertiary amine complexes.

Once the above alkylaluminum hydride-containing liquid phase and the residual solids phase have been formed it is a very simple matter to effect a separation therebetween. Filtration, centrifugation and the like will most commonly be used. Thereupon the separated liquid phase is subjected to the thermal decomposition process as described in detail in said copending application Ser. No. 42,555 so that high purity aluminum, hydrogen and trialkylaluminum are formed.

When utilizing aluminum-silicon alloys as a source of aluminum for use in the foregoing initial step of the comprehensive decomposition processes, it is not always necessary (although it is preferable) to introduce a preformed thermal dissociation catalyst into the heating zone in order to produce the purified aluminum.

metal. Without desiring to be bound by theoretical considerations, it appears that one or more of the impurity metals initially present in the aluminum-silicon alloy (perhaps titanium, vanadium, or the like) tend to form a thermal dissociation catalyst in situ, a small proportion of which appears to be carried into the heating zone along with the alkylaluminum hydride-containing stream. Therefore, by judicious selection of an appropriate aluminum-silicon alloy in the light of a few pilot experiments it may be found entirely feasible to conduct the heating operation without introducing into the system a thermal dissociation catalysts. However, for most practical operation it is preferable to utilize such thermal dissociation catalysts in any thermal decomposition operation, inasmuch as these added catalysts insure that the aluminum, gaseous hydrogen and trialkylaluminum coproduct will be produced very rapidly without appreciable liberation of free hydrocarbon (e.g., olefin).

When conducting the hydroalumination reaction for converting the aluminum-silicon alloy into an alkylaluminum hydride-containing product for use in the thermal decomposition reaction, it is desirable though not essential, to employ a relatively small amount of sodium, sodium hydride or like material to enhance the reactivity of the system. Further details concerning such procedures may be found, for example, in U.S. Pat. No. 3,050,541.

Some examples of thermal decomposition processes wherein an aluminum-silicon-titanium-iron or quaternary alloy is employed in the hydroalumination step are set forth hereinafter in Examples G through J.

EXAMPLE G An essentially equimolar mixture of diethylaluminum hydride and triethylaluminum was prepared by hydroalumination of an aluminum-silicon-iron-titanium quaternary alloy with triethyl-aluminum and hydrogen at 110C and 2000 psi. A solution (40 ml) containing about 75 weight percent of this diethylaluminum hydride-triethylaluminum mixture and about 25 weight percent of trimethyl amine was heated to C and at this temperature 5 milliliters of N,N,N,N" tetramethylethylene diamine and 0.0005 milliliters of titanium tetraisopropoxide were added. Within 3 minutes at 70C decomposition had occurred as evidenced by the formation of aluminum powder and evolution of gaseous hydrogen. In this reaction 1.1 grams of aluminum, an essentially quantitative yield, was obtained.

In a similar run, an additional 40 milliliter portion of the above solution containing about weight percent of the above diethylaluminum hydride-triethylaluminum mixture and about 25 weight percent of trimethyl amine was heated to 70C. While at this temperature,approximately 0.5 milliliter of N,N,N,N- tetramethylethylene diamine and 0.0005 milliliter of titanium tetraisopropoxide were added. Within 10 minutes the decomposition had occurred (aluminum was formed and hydrogen was evolved). Once again, an essentially quantitative yield (1.1 grams) of aluminum was recovered.

EXAMPLE H In this operation a quaternary aluminum-silicon alloy was used to produce a reaction system composed of diethylaluminum hydride and triethylaluminum. In this hydroalumination reaction tertiary amine was present throughout. More particularly, in a 300-milliliter Magne-Stir autoclave were placed milliliters of triethylaluminum, 10 milliliters of N,N,N,N- tetramethylethylene diamine, 0.2 gram of sodium, and 10 grams of powdered alloy (below 325 mesh) containing 68 weight percent aluminum, 27 weight percent silicon, 3 weight percent iron, and 2 weight percent titanium. The bomb was closed and stirring was started. The contents of the bomb were heated to 110C under a hydrogen atmosphere at 2000 psi. Reaction occurred immediately. After one hour of continuous heating and stirring the autoclave was cooled to room temperature and the hydrogen gas vented. The contents of the bomb were filtered to remove the residual silicon, iron, titanium and unreacted aluminum. This solid residue was washed with benzene and vacuum dried. X-ray analysis of this metallic residue showed 77 percent silicon, 8 percent aluminum and 15 percent others (iron and titanium intermetallics). This corresponds to approximately 95 percent utilization of the free aluminum present in the initial alloy.

Twenty-five Milliliters of the liquid reaction product was added to a 100-milliliter round bottom one-neck flask and immersed in an oil bath at 160C. Upon introduction of 0.02 milliliter of titanium tetraisopropoxide, formation of metallic aluminum and evolution of gaseous hydrogen commenced. After approximately minutes the thermal decomposition reaction was essen tially complete. The aluminum produced in this second stage was high purity and the gaseous effluent was substantially entirely gaseous hydrogen.

EXAMPLE I The hydroalumination procedure of Example H was repeated except that 0.01 milliliter of titanium tetraisopropoxide was added to the hydroalumination reactants. On reaching reaction temperature (110C) the reaction commenced immediately and was allowed to proceed for 1 hour. The residual solids were filtered off, washed with benzene and dried yielding a total of 4.57 grams. On analysis, this residue was found to contain 74 percent silicon, 13 percent aluminum, 13 percent others, corresponding approximately to a 92 percent utilization of the free aluminum of the initial alloy.

Twenty-five Milliliters of the liquid reaction product was heated to 140C in an oil bath for a period of approximately 30 minutes. During this time aluminum slowly precipitated and gaseous hydrogen was evolved.

Another 25 milliliters of this same liquid reaction product was subjected to the thermal decomposition reaction except that in this instance 0.02 milliliter of titanium tetraisopropoxide was utilized as the thermal dissociation catalyst. It was found that at 160C metallic aluminum and gaseous hydrogen were evolved at a rapid rate--the reaction was substantially complete within 5 to minutes.

In both cases the metallic aluminum product was of high purity. Likewise in both instances the gaseous effluent from the thermal decomposition reaction was substantially entirely gaseous hydrogen.

EXAMPLE J The hydroalumination procedure as described in Example G above was applied utilizing 14 grams of the above quaternary aluminum-silicon alloy, 0.5 gram of sodium, 87 milliliters of triethylaluminum, and 15 milliliters of tributyl amine. This mixture was heated to l 10C under an atmosphere of 1000 psi hydrogen for 2 hours. Thereupon the reaction mixture was cooled to room temperature and the solids filtered off. After separation of these solids approximately milliliters of alkylalurninum hydride-containing product remained.

A 25 milliliter aliquot of this reaction solution was mixed with 25 milliliters of tributyl amine and heated to C for about 15 minutes. During this time hydrogen evolved and aluminum metal precipitated. Upon cooling and filtering, the amount of aluminum metal produced was found to be 0.15 gram. A sample of this aluminum was subjected to emission spectrographic analysis and was found to contain a maximum of 0.1 percent silicon and a maximum of 0.02 percent of iron. Titanium was not detected and the remainder was aluminum. Thus, within the limits of the accuracy of the analytical procedure used, the aluminum produced in this process was found to be at least 99.8 percent pure.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof and various changes may be made within the scope of the appended claims without departing from the spirit of the invention.

What is claimed is:

1. A method for producing alkylalurninum compounds, which comprises reacting an aluminum-silicon ternary or a quaternary alloy comprising 33 to 94 percent by weight of aluminum, 5 to 58 percent by weight of silicon, 0 to 5 percent by weight of iron, and 0.2 to 4 percent by weight of titanium with an alkylalurninum compound, hydrogen and a catalyst containing an alkali metal or alkaline earth metal.

2. The method of claim 1, wherein said aluminum-silicon alloy is a quaternary alloy comprising 0.6 to 3 percent by weight of titanium, and l to 4 percent by weight of iron.

3. A method according to claim 1, wherein said reaction is effected at a temperature between 70C and 250C.

4. A method according to claim 1, wherein said reaction is effected at a temperature between 100C and 180C.

5. A method according to claim 1, wherein said catalyst has the formula MY,,-Al(C H )RX, wherein M is an alkali metal or alkaline earth metal; Y is hydrogen, chlorine, fluorine, hydroxyl group, cyanide group, alkyl group or alkoxy group; n is an integer in accordance with the valences of M and Y; R is hydrogen or a hydrocarbyl group having up to 20 carbon atoms; and X is hydrogen, halogen or hydrocarbyl group having up to twenty carbon atoms.

6. A method according to claim 1, wherein said catalyst is a sodium alkylalurninum compound or a sodium alkyl-alurninum hydride.

7. A method according to claim 1, wherein said catalyst has the general formula of R My wherein R is a member selected from the group consisting of alkoxy, aroxy, alkaroxy, aralkoxy, alkyl, aryl, aralkyl and alkaryl radicals, Y is a member selected from the group consisting of alkoxy, aroxy, aralkoxy and alkaroxy radicals, M is a metal element selected from the group consisting of lithium, sodium, potassium and magnesium and n is 0 when M is sodium, potassium or lithium and 1 when M is magnesium.

8. A method according to claim 1, wherein said catalyst is selected from the group consisting of sodium metal and sodium hydride.

9. A method of making alkylaluminum compounds comprising: reacting a ternary of quaternary aluminum alloy, comprising by weight 33 to 94 percent aluminum, 5 to 58 percent silicon, 0.2 to 4 percent titanium and up to 5 percent iron, with a mixture selected from the group consisting of an alkylaluminum compound and hydrogen or an alkylaluminum compound, hydrogen and an olefin, the said alkylaluminum compound having the general formula of RR'AlR"; wherein R and R are alkyl radicals having from two to carbon atoms, and R" is an alkyl radical or in the presence of an olefin, hydrogen; in the presence of a catalyst or activating agent having the general formula MY 'AKCH )RX, wherein M is an alkali metal or alkaline earth metal; Y is hydrogen, chlorine, fluorine, hydroxyl group, cyanide group, alkyl group or alkoxy group; n is an integer in accordance with the valences of M and Y; R is hydrogen or a hydrocarbyl group having up to 20 carbon atoms; and X is hydrogen, halogen or hydrocarbyl group having up to 20 carbon atoms.

10. The method of claim 9, wherein the titanium in said quaternary alloy is 0.6 to 3 percent by weight and the iron in said quaternary alloy is l to 4 percent by weight.

11. A method according to claim 9, wherein said olefin is an alpha-olefin having 2 to twenty carbon atoms.

12. A method according to claim 9, wherein said reaction is effected at a temperature between 70C and 250C.

13. A method according to claim 9, wherein said reaction is effected at a temperature between 100C and 180C.

14. The method of claim 9, wherein the alkali metal is selected from the group consisting of sodium, potassium or lithium.

15. The method of claim 9, wherein the alkaline earth metal is selected from the group consisting of calcium or magnesium.

16. The method of claim 9, wherein the catalyst or activating agent is sodium ethylaluminum hydride.

17. The method of claim 9, wherein the reaction in conducted in an inert hydrocarbon medium.

18. The method of claim 9, wherein when an olefin is reacted, the olefin contains catalytic amounts of ethylene.

19. The method of claim 9, wherein the alkylaluminum compound is a member selected from the group consisting of triethylaluminum, di-n-propyaluminum hydride, tri-n-propylaluminum, triisobutylaluminum, diisobutylaluminum hydride and mixtures thereof.

20. A method for producing alkylaluminum compounds which comprises reacting an aluminum-silicon ternary alloy containing as the third principal element titanium in an amount sufficient to speed up the reaction, with an alkylaluminum compound, hydrogen and a catalyst containing an alkali metal or alkaline earth metal.

21. The method of claim 20, wherein said reaction is carried out in the presence of an olefin.

22. The method of claim 21, wherein said olefin is an alpha-olefin having from 2 to twenty carbon atoms.

23. The method of claim 20, wherein said ternary alloy consists essentially of 33 to 94 percent by weight of aluminum, 5 to 5 8 percent by weight of silicon and 0.2-4 percent by weight of titanium.

24. The method of claim 23, wherein the amount of titanium in said ternary alloy is 0.6 to 3 percent by weight.

25. The method of claim 20, wherein said catalyst has the formula MY,,'Al(C H -,)RX, wherein M is an alkali metal or alkaline earth metal; Y is hydrogen, chlorine, fluorine, hydroxyl group, cyanide group, alkyl group or alkoxy group; n is an integer in accordance with the valences of M and Y; R is hydrogen or a hydrocarbyl group having up to 20 carbon atoms; and X is hydrogen, halogen or hydrocarbyl group having up to twenty carbon atoms.

26. A method for producing alkylaluminum compounds, which comprises reacting a quaternary alloy comprising 33 to 94 percent by weight of aluminum, 5 to 58 percent by weight of silicon, l to 5 percent by weight of iron, and 0.2 percent to 4 percent by weight of titanium, with a catalyst containing an alkali metal or alkaline earth metal, an aluminum alkyl compound and hydrogen at an elevated temperature.

27. The method of claim 26, wherein said quaternary alloy comprises 0.6 to 3 percent by weight of aluminum and l to 4 percent by weight of iron.

28. The method of claim 26, wherein said reaction is carried out in the presence of an olefin.

29. The method of claim 28, wherein said olefin is an alpha-olefin having from 2 to twenty carbon atoms.

30. The method of claim 26, wherein the reaction is conducted at a temperature from about C to about 250C.

31. The method of claim 26, wherein the catalyst or activating agent is sodium ethylaluminum hydride.

32. The method of claim 26, wherein the reaction is carried out in an inert hydrocarbon medium.

33. The method of claim 26, wherein when an olefin is reacted, the olefin contains catalytic amounts of ethylene.

34. In a process of preparing aluminum alkyl from aluminum in the presence of hydrogen and an aluminum alkyl, the improvement wherein the aluminum is employed in the form of an aluminum-silicon-irontitanium alloy containing at least some metallic aluminum not held in the tightly bound form of an intermetallic compound.

35. The process of claim 34 further characterized in being performed in the additional presence of an alphaolefin.

36. The process of claim 34 further characterized in being performed in the additional presence of an alphaolefin selected from the group consisting of ethylene, propylene and isobutylene.

37. In a process of preparing aluminum alkyl from aluminum in the presence of hydrogen and an aluminum alkyl at an elevated temperature and pressure, the improvement wherein the source of the aluminum for the reaction is an aluminum-silicon-iron-titanium alloy which contains at least about 3 weight percent iron, at least about 2 weight percent titanium, and at least some metallic aluminum which is not held in the tightly bound form of an interrnetallic compound.

38. The process of claim 37 further characterized in being performed in the additional presence of ethylene, propylene, or isobutylene.

39. The process of claim 37 further characterized in that said alloy contains about 68 weight percent aluminum, about 27 weight percent silicon, about 3 weight percent iron and about 2 weight percent titanium.

40. In a process of preparing alkylaluminum from held in the tightly bound form of an intermetallic comaluminum in the presence of hydrogen, an aluminum pound. alkyl, and a l'eldth'ely Small amount of sodlum or sodi' 41. The process of claim 40 further characterized in um hydride to enhance the reactivity of the system, the improvement wherein the aluminum is employed in the gi gg g g zgfigzx presence of ethylene form of an aluminum-silicon-iron-titanium alloy which contains at least some metallic aluminum which is not 

2. The method of claim 1, wherein said aluminum-silicon alloy is a quaternary alloy comprising 0.6 to 3 percent by weight of titanium, and 1 to 4 percent by weight of iron.
 3. A method according to claim 1, wherein said reaction is effected at a temperature between 70*C and 250*C.
 4. A method according to claim 1, wherein said reaction is effected at a temperature between 100*C and 180*C.
 5. A method according to claim 1, wherein said catalyst has the formula MYn.Al(C2H5)RX, wherein M is an alkali metal or alkaline earth metal; Y is hydrogen, chlorine, fluorine, hydroxyl group, cyanide group, alkyl group or alkoxy group; n is an integer in accordance with the valences of M and Y; R is hydrogen or a hydrocarbyl group having up to 20 carbon atoms; and X is hydrogen, halogen or hydrocarbyl group having up to twenty carbon atoms.
 6. A method according to claim 1, wherein said catalyst is a sodium alkylaluminum compound or a sodium alkyl-aluminum hydride.
 7. A method according to claim 1, wherein said catalyst has the general formula of RnMy wherein R is a member selected from the group consisting of alkoxy, aroxy, alkaroxy, aralkoxy, alkyl, aryl, aralkyl and alkaryl radicals, Y is a member selected from the group consisting of alkoxy, aroxy, aralkoxy and alkaroxy radicals, M is a metal element selected from the group consisting of lithium, sodium, potassium and magnesium and n is 0 when M is sodium, potassium or lithium and 1 when M is magnesium.
 8. A method according to claim 1, wherein said catalyst is selected from the group consisting of sodium metal and sodium hydride.
 9. A method of making alkylaluminum compounds comprising: reacting a ternary or quaternary aluminum alloy, comprising by weight 33 to 94 percent aluminum, 5 to 58 percent silicon, 0.2 to 4 percent titanium and up to 5 percent iron, with a mixture selected from the group consisting of an alkylaluminum compounD and hydrogen or an alkylaluminum compound, hydrogen and an olefin, the said alkylaluminum compound having the general formula of RR''AlR''''; wherein R and R'' are alkyl radicals having from two to 20 carbon atoms, and R'''' is an alkyl radical or in the presence of an olefin, hydrogen; in the presence of a catalyst or activating agent having the general formula MYn.Al(C2H5)RX, wherein M is an alkali metal or alkaline earth metal; Y is hydrogen, chlorine, fluorine, hydroxyl group, cyanide group, alkyl group or alkoxy group; n is an integer in accordance with the valences of M and Y; R is hydrogen or a hydrocarbyl group having up to 20 carbon atoms; and X is hydrogen, halogen or hydrocarbyl group having up to 20 carbon atoms.
 10. The method of claim 9, wherein the titanium in said quaternary alloy is 0.6 to 3 percent by weight and the iron in said quaternary alloy is 1 to 4 percent by weight.
 11. A method according to claim 9, wherein said olefin is an alpha-olefin having 2 to twenty carbon atoms.
 12. A method according to claim 9, wherein said reaction is effected at a temperature between 70*C and 250*C.
 13. A method according to claim 9, wherein said reaction is effected at a temperature between 100*C and 180*C.
 14. The method of claim 9, wherein the alkali metal is selected from the group consisting of sodium, potassium or lithium.
 15. The method of claim 9, wherein the alkaline earth metal is selected from the group consisting of calcium or magnesium.
 16. The method of claim 9, wherein the catalyst or activating agent is sodium ethylaluminum hydride.
 17. The method of claim 9, wherein the reaction is conducted in an inert hydrocarbon medium.
 18. The method of claim 9, wherein when an olefin is reacted, the olefin contains catalytic amounts of ethylene.
 19. The method of claim 9, wherein the alkylaluminum compound is a member selected from the group consisting of triethylaluminum, di-n-propyaluminum hydride, tri-n-propylaluminum, triisobutylaluminum, diisobutylaluminum hydride and mixtures thereof.
 20. A method for producing alkylaluminum compounds which comprises reacting an aluminum-silicon ternary alloy containing as the third principal element titanium in an amount sufficient to speed up the reaction, with an alkylaluminum compound, hydrogen and a catalyst containing an alkali metal or alkaline earth metal.
 21. The method of claim 20, wherein said reaction is carried out in the presence of an olefin.
 22. The method of claim 21, wherein said olefin is an alpha-olefin having from 2 to twenty carbon atoms.
 23. The method of claim 20, wherein said ternary alloy consists essentially of 33 to 94 percent by weight of aluminum, 5 to 58 percent by weight of silicon and 0.2-4 percent by weight of titanium.
 24. The method of claim 23, wherein the amount of titanium in said ternary alloy is 0.6 to 3 percent by weight.
 25. The method of claim 20, wherein said catalyst has the formula MYn.Al(C2H5)RX, wherein M is an alkali metal or alkaline earth metal; Y is hydrogen, chlorine, fluorine, hydroxyl group, cyanide group, alkyl group or alkoxy group; n is an integer in accordance with the valences of M and Y; R is hydrogen or a hydrocarbyl group having up to 20 carbon atoms; and X is hydrogen, halogen or hydrocarbyl group having up to twenty carbon atoms.
 26. A method for producing alkylaluminum compounds, which comprises reacting a quaternary alloy comprising 33 to 94 percent by weight of aluminum, 5 to 58 percent by weight of silicon, 1 to 5 percent by weight of iron, and 0.2 percent to 4 percent by weight of titanium, with a catalyst containing an alkali metal or alkaline earth metal, an aluminum alkyl compound and hydrogen at an elevated temperature.
 27. The method of claim 26, wherein said quaternary alloy comprises 0.6 to 3 percent by weight of aluminum and 1 to 4 percent by weight of iron.
 28. The method of claim 26, wherein said reaction is carried out in the presence of an olefin.
 29. The method of claim 28, wherein said olefin is an alpha-olefin having from 2 to twenty carbon atoms.
 30. The method of claim 26, wherein the reaction is conducted at a temperature from about 70*C to about 250*C.
 31. The method of claim 26, wherein the catalyst or activating agent is sodium ethylaluminum hydride.
 32. The method of claim 26, wherein the reaction is carried out in an inert hydrocarbon medium.
 33. The method of claim 26, wherein when an olefin is reacted, the olefin contains catalytic amounts of ethylene.
 34. In a process of preparing aluminum alkyl from aluminum in the presence of hydrogen and an aluminum alkyl, the improvement wherein the aluminum is employed in the form of an aluminum-silicon-iron-titanium alloy containing at least some metallic aluminum not held in the tightly bound form of an intermetallic compound.
 35. The process of claim 34 further characterized in being performed in the additional presence of an alpha-olefin.
 36. The process of claim 34 further characterized in being performed in the additional presence of an alpha-olefin selected from the group consisting of ethylene, propylene and isobutylene.
 37. In a process of preparing aluminum alkyl from aluminum in the presence of hydrogen and an aluminum alkyl at an elevated temperature and pressure, the improvement wherein the source of the aluminum for the reaction is an aluminum-silicon-iron-titanium alloy which contains at least about 3 weight percent iron, at least about 2 weight percent titanium, and at least some metallic aluminum which is not held in the tightly bound form of an intermetallic compound.
 38. The process of claim 37 further characterized in being performed in the additional presence of ethylene, propylene, or isobutylene.
 39. The process of claim 37 further characterized in that said alloy contains about 68 weight percent aluminum, about 27 weight percent silicon, about 3 weight percent iron and about 2 weight percent titanium.
 40. In a process of preparing alkylaluminum from aluminum in the presence of hydrogen, an aluminum alkyl, and a relatively small amount of sodium or sodium hydride to enhance the reactivity of the system, the improvement wherein the aluminum is employed in the form of an aluminum-silicon-iron-titanium alloy which contains at least some metallic aluminum which is not held in the tightly bound form of an intermetallic compound.
 41. The process of claim 40 further characterized in being performed in the additional presence of ethylene, propylene, or isobutylene. 